In recent years, with the heightening of performance of engines such as increase in power, use environment of piston rings for engines has become severer, and piston rings having more excellent abrasion resistance and burning resistance have been demanded (refer to the following patent literatures 1 to 4). In particular, the outer peripheral surface of a piston ring which slides with a cylinder liner is required to have high abrasion resistance and burning resistance and the like. For responding to such requirements, high abrasion resistance and burning resistance have been imparted to piston rings by forming a coating on the outer peripheral sliding surfaces of piston rings by a thermal spraying method. Incidentally, “burning” is such a phenomenon that the outer peripheral surface of a piston ring (a sliding surface) is joined with the cylinder liner by heat generation due to sliding with the cylinder liner. “Burning resistance” is the property of resisting burning.
For example, as a method to heighten abrasion resistance of a thermal spray coating, a method of increasing a ceramic component contained in the thermal spray coating as hard particles has been taken.